The heartfelt tribute came as a top neurosurgeon warned Schumacher's chances of recovery were decreasing.

Andreas Ferbert, President of the German society for Neuro Intensive and Emergency Medicine, told a conference that the forecast "deteriorating" the longer he is kept in an artificial coma,

Neurological experts at the medical summit in Hanover were told the greatest danger for the seven-time F1 world champion is the loss of cognitive functions if he was woken up.

His lungs, immune system and kidneys could all sustain lasting harm the longer he receives the anaesthetics to keep him sedated.

Schumacher, 45, is being treated at the University Hospital of the French city of Grenoble following his low-speed ski accident on the slopes in Meribel on December 29 when he plunged on to rocks and split his helmet open.

He was airlifted to safety and doctors at first feared he would not survive the night.

He was plunged into an artificial coma to give the brain a chance to heal and underwent two operations but remains critically ill.

At his bedside has been placed his beloved wooden-beaded Shamballa bracelet, his good-luck talisman which he wore for all his 307 F1 races during his conquest of seven F1 world titles.

The bracelet was found last week in a snowdrift at the site of his accident and driven from Meribel to be handed over to Schumacher's wife Corinne, 44, who is with her husband and their two children.